Junctional, AV Block & Ventricular Arrhythmias – Week 3 Units 1.4-1.6

Fill-in-the-blank flashcards covering key concepts of junctional rhythms, AV blocks, ventricular arrhythmias, their ECG characteristics, clinical significance, and treatments.

In a junctional rhythm, impulses travel retrograde up to the atria and antegrade down to the ventricles, producing an __ P wave in lead II.

inverted

When the inverted P wave appears before the QRS in a junctional beat, the PR interval is typically __ seconds.

less than 0.12

A single early beat from the AV junction that interrupts an underlying rhythm is called a __.

Premature Junctional Contraction (PJC)

Less than three consecutive junctional escape beats are simply called junctional escape beats, whereas three or more constitute a __.

Junctional Escape Rhythm

The inherent rate of a junctional escape rhythm is __ bpm.

40 – 60

A junctional rhythm with a rate of 60-100 bpm is termed __.

Accelerated Junctional Rhythm

A junctional rhythm with a rate of 100-180 bpm is termed __.

Junctional Tachycardia

Supraventricular tachycardia (SVT) generally refers to rhythms with rates above __ bpm in which P waves are difficult to discern.

150-160

Paroxysmal episodes of SVT that begin and end abruptly are abbreviated __.

PSVT

According to ACLS, unstable SVT with a ventricular rate >150 bpm should be treated first with __.

synchronized cardioversion

First-degree AV block is identified by a constant PR interval greater than __ seconds.

0.20

In Mobitz I (Wenckebach), the PR interval progressively __ until a QRS is dropped.

lengthens

Mobitz II is distinguished by a constant PR interval with periodic dropped QRS complexes and is often expressed as an atrial-to-ventricular __ (e.g., 3:1).

conduction ratio

Complete absence of conduction from atria to ventricles is called __ heart block.

Third-degree (Complete)

In third-degree block, if the escape focus is junctional the ventricular rate is typically __ bpm.

40-60

Atropine is ineffective for treating __ and third-degree AV blocks.

Second-degree Type II (Mobitz II)

PVCs display no preceding P wave and a wide, bizarre QRS complex of __ seconds or more.

0.12

A PVC falling on the downslope of the T wave is termed the __ phenomenon.

R-on-T

More than six PVCs per minute, couplets, or multifocal PVCs are considered __.

dangerous (high ventricular irritability)

A run of three or more PVCs at 150-250 bpm constitutes __.

Ventricular Tachycardia

Polymorphic VT with QRS complexes that twist around the baseline is called __.

Torsades de Pointes

Chaotic, quivering ventricular activity with no identifiable waves is __.

Ventricular Fibrillation

The only ventricular rhythm produced by an escape mechanism at 15-40 bpm is __.

Idioventricular Rhythm

Idioventricular rhythm exceeding 40 bpm but below 100 bpm is termed __ idioventricular rhythm.

Accelerated

A straight-line ECG with no electrical activity represents __.

Asystole

Before declaring asystole, always confirm in __ leads.

two

Evidence of organized electrical activity without a palpable pulse defines __.

Pulseless Electrical Activity (PEA)

PVCs occurring every second beat are called __.

bigeminy

Two consecutive PVCs are referred to as a __.

couplet

PVCs from different ventricular foci exhibiting different morphologies are termed __ PVCs.

multifocal

Three PVCs separated by two normal beats (every third beat) describe __.

trigeminy

The fail-safe rhythm that may appear in well-trained athletes with slow resting rates is the __.

Junctional Escape Rhythm

Junctional tachycardia commonly results from AMI, open-heart surgery, myocarditis, or __ toxicity.

digoxin (digitalis)

Second-degree Type I block often follows an __ myocardial infarction.

inferior

Mobitz II block is associated with anterior MI or conditions such as __ toxicity or hyperkalemia.

digoxin

In third-degree block with a ventricular focus, the QRS is typically __ seconds wide.

0.12

Accelerated junctional rhythm indicates an __ AV junction overriding the SA node.

irritable

SVT initial management includes vagal maneuvers such as __ or bearing down.

carotid massage (if no bruits present)

PVCs that do not interrupt the underlying rhythm and lack a compensatory pause are termed __ PVCs.

interpolated

Ventricular tachycardia at rates below 150 bpm is labeled __ VT.

slow

The most common reversible cause of pulseless electrical activity is __.

hypoxia secondary to respiratory failure

Bundles of His pacemaker cells situated where the AV node merges with the His bundle generate __ arrhythmias.

junctional

In first-degree AV block, there are no __ beats; every P wave is followed by a QRS.

dropped or skipped

The compensatory pause following a PVC makes the next sinus beat arrive __ on schedule.

right

Second-degree Type I block R-R intervals are described as __ irregular.

regularly

Treatment of symptomatic Mobitz I usually involves administration of __.

Atropine

The lethal ventricular rhythm incompatible with life that requires immediate defibrillation is __.

Ventricular Fibrillation

Idioventricular rhythm often reflects a large __ with extensive ventricular damage.

myocardial infarction